Station, Transforming.
In alternating current distribution, a building or place where a number
of transformers are worked, so that low potential or secondary circuits
are distributed therefrom.
Steel.
A compound of iron with carbon. The carbon may range from a few
hundredths of one per cent. up to two per cent. For magnets, tool steel
drawn to a straw color or a little lower is good. All shaping and filing
should be done before magnetization.
Steeling.
The deposition of iron on copper plates by electrolysis. In
electrotyping a thin deposit of iron is thus given the relief plates
before printing from them. The deposit is very hard and exceedingly
thin, so that it does not interfere with the perfection of the
impression in the printing process. As the iron becomes worn it can be
dissolved off with hydrochloric acid, which does not dissolve the
copper, and a new deposit can be given it. Thus the plate may last for
an indefinite number of impressions.
The iron bath may be prepared by immersing in a solution of ammonium
chloride, two plates of iron, connected as anode and kathode in a
circuit. One plate dissolves while hydrogen is given off from the other.
The solution thus produced is used for a bath.
The hardness of the deposit, which is really pure iron, gives the name
of "steeling."
Synonym--Acierage.
St. Elmo's Fire.
Luminous static discharge effects sometimes seen on objects elevated in
the air. They are especially noticed on ships' masts. The sailors term
them corpusants (holy bodies). They resemble tongues or globes of fire.
Step-by-step Telegraphy.
A system of telegraphy in which in the receiving instrument a hand is
made to move step-by-step, with an escape movement around a dial. For
each step there is a letter and the hand is made to stop at one or the
other letter until the message is spelled out. (See Dial Telegraph.)
Step-down. adj.
A qualification applied to a converter or transformer in the alternating
current distribution, indicating that it lowers potential difference and
increases current from the secondary.
Step-up. adj.
The reverse of step-down; a qualification of a transformer or converter
indicating that it raises the potential and decreases the current in the
secondary.
Sticking.
The adherence, after the current is cut off, of the armature to the
poles of a magnet. In telegraphy it is a cause of annoyance and
obstructs the working. It may, in telegraphy, be due to too weak a
spring for drawing back the armature, or to imperfect breaking of the
contact by the despatcher's key or by the receiver's relay.